Accelerator of vulcanization



Patented June 8, 1943 2,321,305 ACCELERATOR F VULCANIZATION William E. Messer, Cheshire, Conn assignor-to United States Rubber Company, New York, N. Y., a corporation of New Jersey No Drawing. Application June 24, 1939, Serial No. 280,929

Claims.

This invention relates to a new class of compounds which have been found valuable as accelerators for the vulcanization of rubber.

The new class of rubber vulcanization accelerators may be represented by the general formula (AX os)x Ar is an arylene group; when n is 1, X is NH-alkyl, NH-aryl, N-diaryl, O-alkyl or O-aryl; when n is 2, X is oxygen, NH, N-alkyl, or N-alicyclic; when n is 3, X is N. Alkyl is intended to include substituted alkyls such as benzyl.

These materials are derivatives of arylene-thiazyl sulfur chloride, wherein the chlorine is replaced by the X radical above, when 13 moles of the arylene-thiazyl sulfur chloride is reacted with a mole of ammonia, primary amines, water, alcohols or phenols. During such reaction hydrogen chloride is split off.

In the following illustrative examples, benzothiazyl sulfur chloride is used as the reagent; it may be prepared in solution, for purposes of reaction by passing dry chlorine into a slurry of 1,1 dithio bis benzothiazole in benzene, carbon tetrachloride, etc.

The accelerators are delayed-action accelerators similar in this respect to 1,1 dithio bis benzothiazole itself. Hence they may be used alone or in conjunction with activating more basic nitrogen compounds such as ammonia, amines, guanidines such as diphenyl guanidine, thiuram sulphides such as tetramethyl thiuram monosulfide, etc. They may also, if desired, be used in admixture with other thiazole accelerators such as the mercapto-benzothiazyl sulfides.

The following examples are given to illustrate the invention in which comparison is made with a stock containing 1,1 dithio bis benzothiazole (parts are by weight) EXAMPLE I The reaction product of benzothiazyl sulfur chloride and aniline sulfamine).

66 grams crude 1,1-dithio bis benzothiazole are stirred with 300 to 600 cc. carbon tetrachloride and dry chlorine passed in until complete solution ensues and about 14.1 grams of chlorine has been absorbed. About '70 cos. of aniline are then added (N-phenyl benzothiazyl with stirring and after standing a short whilethe resulting solution is filtered and the precipitatewashed with a little carbon tetrachloride, recovering some 47 grams pure aniline hydrochloride (aniline salt). The carbon tetrachloride filtrates are evaporated to dryness (condensing and recovering carbontetrachloride used) leaving grams of dark gray, oily crystals. These may be purified by washing with alcohol and drying, thereby obtaining 60 grams of light gray colored crystals, melting at 119-122 C.

' canized and tested.

Stock Suprex c1ay Zinc soap of cocoanut o Sulfur 1,1-dithio bis beuzothiazol. N-phenyl benzo thiazyl sulfamine.

Tensiles-unaged A B Minutes cure at 30 lbs/sq. in. steam pressure T E '1 E Search test A B Minutes cure at 5 lbs/sq. in.

steam pressure "1 E T E 132 1-, 330 225 1,437 1, 515 200 1, 280 137 l, 445 203 1, 243 V 1, 337 210 l, 197 192 1, 050 215 l, 107 306 652 2 47 852 855, 577 275 810 T=ulti1nate tensiles in pounds per square inch. E==percentelongationatbnak. I

EXAMPLE ii Twenty ccs. liquid ammonia were dissolved in about 300ccs. carbon tetrachloride and to this solution were added with stirring 150 ccs. carbon water. The resulting material was boiled to recover carbon tetrachloride used, cooled, precipitated, filtered off, washed and dried, obtaining 6.1 grams of a. product having melting range 157- tetrachloride solution of 20 grams benzothiazyl ig g i gig gg gg g i gg fi g g g i sulfur chloride. Carbon tetrachloride solvent was i y 7 4 2 3 recovered by evaporation and 22.5 grams residue 7 onsists essential] or was treated with water and precipitated, washed p I y thoroughly, and dried giving 16.6 of a product 10 /N having a melting range 140-155 with decomposition and 12.4% nitrogen (theory=12.1% nitrogen). s 1

Yield is 96% theory based on dibenzothiazyl diulfide used The following rubber mixes were made, vulr- The product obtained from the above reaction Canlzed d testedconsists essentially of: 1

.. N Stock E F C S NH Pale crepe 100 100 Zinc oxide 10 Llthopou 40 40,

s 2 Whiting 50 50 I v Suprex clay r. 25

r vTh following rubber mixes were made, vulsoap orcocoanutoilacids 1 i um 3 t m d tested- 1,1-dithio bis benzothiazole 0, 65 l 25 Reaction product of ExampleSabovc 0, 65

Stock C D Y I Tenszles-unaged Pale crepe 100 100 Zinc oxide 10 10 r E F tti fi f g8 g8 'Minutes cure at lbs/sq. in.

Suprex i 25 25 30 steam pressure Zinc soap of cocoanut E T E l 10 1S BBZO 18108..-

Accelerator oi Example2above 28g 1 :38 603 2: 360 610 Tensiles-unage i C D Minutes we at 30 lbs-[Sq in. Tenszles Aged 168 hours 211. oxygen steam pressure 'r E 'r E 40 E F v 7 Minutes cure at 30 lbs/sq. in.

773 200 773 steam pressure 550 1,200 E T E 252 :83

1 476 700 466 573 $5330 500 1, 350 516 566 1, 570 53a Tensiles+aged 6'd ys in oxy en; 33% "33 525 0 ID. I Minutes cure at 30 lbs/sq. in. Search test steam pressure 7 Y i '11 E T E I F F Minutes cure at 5 lbs/sq. in. 565 400 515 St Pressure 485 1,150 540 2,110 .535 2,000 540 1, 500

Scorch test 2' o 1) I Minutestcure at 5 lbs/sq. in.

S eam IGSSUIG p '1 E 'r E EXAMPLE IV To a mixture of 20 grams 1,1' dithio bis benzothiazole and ccs. carbon tetrachloride was added the theoretical amount of chlorine and this product added to 400 ccs. water, slowly, with 190 820 900 strong agitation. Stirred for 2 hours mor while heating to drive off solvent which may be condens d and r cov red. l EXAMPLE III e e e Fina 1y cooled with stir 8.6 grams 1,1'-dithio-bis-benzothiazole (crude) treated with theoretical amount of chlorine and '50 ccs. carbon tetrachloride and the product added gradually with good agitation to. 20 cos. concentrated ammonium hydroxide and 200 ccs.

ring and filtered off precipitate, washed and dried. Fifteen grams of nearly white product having'a melting range of Isl-169 C; The percent nitrogen was..8.14% 'based on the pure 1,1- dithio bis benzothiazole (theory is 8.05% nitrogen)." 4 Y The structure is believed to be: 'Tensilesunayed Minutes icure at 30 lbs./

sq. in. S 88m 115851116 2 5 p T E T E The following rubber stocks were made, vul- (l) 0) canized and tested: 1 400 13 2 390 13 Y 3'23?) 232 as 223 Smk G E 21220 626 21540 603 Pal cre e 1 0 100 i [Ri a i No cure. Lithopnne 40 40 whufinu 5o 50 Tmzszles-aged 72 hours at 212 F. Suprex clay 25 25 Zinc soap of cocoanut oil acid 1 Y 1 Sulfur 3 3 1,1'-dithio bisbelizothiazole 0.65 I J Accelerator of Example 4 above.-. 0. 65 Minutes cure at 30 lbs./

sq. in. steam pressure 'l E T E Tenszles-unaged (l G H 1,080 520 790 423 Minutes cure at 30 lbs./sq. in. 860 506 690 336 steam pressure 900 500 750 350 T E T E 790 470 e80 336 40 1 210 900 {4-70 1 No cure 1,850 583 Scorch test 2,200 580 Y 2, 350 666 I I J Tenszlesaged 6 days m oxygen Minutes cure at51bs.l

j sq. in. steam pressure T E T E G H Minutestcure at 30 lbsJsq. in. V 1

s eam pressure T E T 0) l a I T Scorch test lilxmvrrras VI G H Mmutestcure at 5lbs./sq.m. Benzotlnazyl sulfur chloride from 16.6 grams s Pressure T E T E 1,1' -dithio bis benzothiazole and 100 cos. carbon tetrachloride was slowly added to a solution of 0 1,305 1,320 23.2 cos. cyclohexylamine in 100 ccs. carbon tet- 3g 3 i rachloride. The resulting solution was filtered 15o 260' 042 m5 732 and washed with carbon tetrachloride and pre-' cipitate dried, recoverin 13.4 grams cyclohexyl- EXAMPLE V amine hydrochloride. The carbon tetrachloride 16.6 grams 1,l.'-dithio bis benzothiazole-were stirred with 100 ccs. carbon tetrachloride and theoretical amount of chlorine absorbed. The resulting solution of benzo thiazyl sulfur chloride was added to a solution of 13 cos. ethylamine in 200 ccs. carbon tetrachloride slowly with agitation. Precipitate forming was filtered off, washed with carbon tetrachloride and dried, recovering '7 .8 grams of ethylamine hydrochloride; All carbon tetrachloride filtrates were evaporated to dryness, recovering carbon tetrachloride and leaving 19.1 grams of a product which is a viscons. brown oil- 1 The following rubber stocks were made. vul-. canized and tested.

Stock I I I Accelerat r 01 Ex mp e 5 ahQve filtrates were evaporated recovering carbon tetrachloride used and a'residual oil obtained which crystallized after several days standing to 23.6 grams white powder, melting range 90 C. and having 9.79% nitrogen. (Theory i 9.8% nitrogen.) The product is believed to have the general formula The following rubber stocks were made, vulcanized and tested.

Stock K L M Pale crepe 100 100 Zinc oxi e. 10 10 1.0 Lithopone 40 40 40 Whiting----. 50 5O 50 Suprex clay 25 25 25 Zinc soap of cocoanut 1 a 1 1 1 Sulfur; 3 3 3 1,1-dithio his benzothiazol 0.65 Accelerator of Example 6 above 0.65 0 325 Tensilesunaged Tensz'ler-filmdfid, ,1. g gs fgg e K L M Minutes cure P in. steam I I g at 30 lbs/sq. 1n. I

sure T E a 'r 'E T E steam Pressure '1. E 'r E T E 560 1,990 566 880 900 2:10 703, 400 850 55s 2, 530 003 1,210 485 1, s 500 1,000 "503 006 2,000 000 2,080 510 2,760 .s10 1,830 045 603 2, 500 00a 2, 230 550 2, 840 59s 2, 400 57s 01s 2, 300 596 2,120 513 2, 600 543 2, 540 500 TensiZes-72 hours at 212 F. Tensilesaged 5 days in oxygen Minutescure K L M N o P at lbs/sq. r Mamiibtes cur e H in. steam pres- 10 St 2 1 2 sure T E, T E '1 E e Fe F 'r E T" '1, 5;

490 1,100 483 010 535 250 535 486 1,120 410 620 455 800 440 450 1, 020 436 040 545 1, 300 400 400 000 390 700 500 1,140 535 ass 900 406 500 490 1, 600 525 Search test Minutes cure K L M 25 1 Minutes cure O P at 5 lbs/sq. in. at 5 lbs./sq. m. steam pressure T E T E T E steam pressure T E I T E T E EXAMPLE. VII

5 grams of butylamine were dissolved 1n 300 ccs. carbon tetrachloride and 20 grams benzo thiazyl sulfur chloride in 150 ccs. carbon tetrachloride were added. The carbon tetrachloride was evaporated and recovered and the residue was taken up in fresh carbon tetrachloride, filtered off precipitate and dried, recovering 11.7 grams butylamine hydrochloride .The carbon tetrachloride filtrates were evaporated to dryness, recovering carbon tetrachloride and leave ing 18.9 grams of a viscous oil having some 10.7 nitrogen (theory for (C7H4NS2)NHC4H9=11.8 and '20 grams 1,1'-dithio bis benzothiazole and 100 ccs. dry benzene were treated with theoretical amount of chlorine and the resulting solution of benzo thiazyl sulfur chloride was added slowly to 18 grams butylamine in 200 ccs. benzene with stirring. The resulting material was filtered to remove butylamine hydrochloride and the filtrate evaporated recovering benzene and leaving 28 grams of the same product as produced in A, as thick paste.

The following rubber stocks were made, vulcanized and tested.

Examples of other "arylamines that may be reacted with benzothiazyl sulfur chlorideJor purposes of-the invention, are alpha naphthylamine, and beta-naphthylamine, giving corresponding N -naphthy1 benzothiazylsulfamines of the character herein disclosed.

When an alcohol (or alcoholate), or phenol (or phenolate) is reacted with the arylene-thiazyl sulfur chloride, compounds of the typeof benzothiazyl ethoxy sulfide, and benzothiazyl phenoxy sulfide are produced, the O-alkyl or O-aryl group being joined to the thiol sulfur atom.

" The invention may be applied'to the vulcanization of natural rubbers as well as artificially prepared rubbers adaptable to vulcanization with sulfur, including reclaimsand latices of such rubber compositions.

I The present invention is not limited to the specific examples. above set forth wherein the preferred accelerators areemployed. Other ratios of the compounding ingredients than those men-. tioned in the examples as well as other well known fillers,pigments and the like may be em ployed inthe production of various types of rubber. compounds as will be apparent to those skilled in the art to which this-invention pertains.

; Having thusdescribed my invention, what I claim: and desire to. protect by Letters Patent is: A method which comprises vulcanizing rub her in the presence of a co pound of the general formula arylene group; 11; is 3, and Xis V 3. The vulcanization product of'a rubber som position containing a compound as set forth in claim 1. Ar os .N-ouzn 4. A method which comprises vulcanizing rub- 2 her in the presence of an arylene thiazyl sulfamine selected from the group consisting of com- 5 H pounds having the respective formulas: Arl /C-SNary1 s A\/ os NH )K where Ar is an arylene group.

S 2 1 5. The vulcanization product of a vulcanizable N rubber composition containing a product of reaction as set forth in claim 4.

WILLIAM E. MESSER. 

